GIMP Version: 2.8.14
Operating System: Windows
GIMP Experience: Basic Level

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Help needed please.

I am editing some photos for a book I'm wrighting. I have placed the subject matter on a blue piece of material and would now like to remove the blue using gimp (and then saving as save as a .png).

I have used 'colour to alpa' but I just cant seem to highlight all the blue with the fuzzy select tool....elements of the blue do work but not all - can anyone suggest how I do this please!!!

Jon

The vignetting in the photo are part of the problem. A re-shoot with different settings might help.
To make a cleaner selection on your current image, give this a go.
1. Add an Alpha Channel, create a duplicate layer.
2. Colors menu > Threshold, left side # reduce to 60-70 or until the vignetting is not on the bars, OK.
3. Select by Colour, Black.
4. Add a Layer Mask, Selection.
5. Select the Layer Mask, paint White to fill in any missing middle parts or black to remove any stray pixels on the background.
6. Mask to Selection, Selection the original layer (needs Alpha Channel) and remove the background.

Is this the result you are looking for?

I duplicated the photograph twice, added an alpha channel to the middle layer, then used a selective gaussian blur of 5 pixels on the top layer.
This removed the textile pattern and I was able to select by colour. I made the middle layer active and used Edit/Clear.
With just a small amount of cleaning up with the erase tool it was possible to have a transparent background.
Saved that as a .png.
Having done that you can put any background you require.

I have overlapped with the answer from Odinbc who has probably offered you a much better solution!

david.

Edit: The photograph appears with a white background. However, if you save it to your computer you will find that an image viewer will show a transparent background.

It's more the 'texture' of the background that gives it a very wide color spread. Re-shoot, yes, but on some uniform background (sheet of glossy paper, or vinyl).

Hi all,

Many many thank for your help. I will try to photograph onto a flat and consistent surface from now on!

However the above solutions are gratefully received, as I have about 40 pictures to edit taken like this....



Jon

I made a photography station for my wife that follows along the same line as this Instructable below. But instead of a paper roll, it's a retractable vinyl window shade. Works like a charm for her.

http://www.instructables.com/id/Easy-Wo ... -Backdrop/